The prion is the agent responsible for transmissible spongiform subacute encephalopathies, in particular human variant CJD. Recent studies have shown that there exists a probable risk of transmission of the prion during blood transfusions. It therefore appears necessary to eliminate the infectious risk related to the prion from blood products intended to be transfused, in the same way as other pathogenic agents.
In the document WO-2004/090102, adsorbent particles in the form of resin capable of selectively binding the prion proteins present in the blood is described. These adsorbent particles are placed in columns.
Likewise, it is now recognized that the substances such as methylene blue or derivatives of psoralen used during the inactivation treatment of blood pathogens must be eliminated from blood products before they are transfused to a patient.
To this end, the document WO-00/74806 describes filtration devices including adsorbent particles such as activated carbon or polystyrene-based resins for eliminating pathogen inactivation substances from blood. These devices are also arranged in the form of columns containing the adsorbent particles.
It appears necessary to improve this type of filtration device comprising adsorbent particles in order in particular to comply with the particular blood filtration constraints, for example in terms of salting-out of the particles in the filtrate, speed of filtration and/or haemolysis of the red corpuscles. It is also important to have available filtration devices able to be easily manufactured, without loss of particles, and sterilized.
The invention therefore aims to propose a filtration unit that meets these requirements and that makes it possible to substantially eliminate a target substance present in the biological fluid whilst leaving the composition of the biological fluid substantially unchanged after filtration.